initial commit, got it running

lua/chameleon/config.lua

@@ -0,0 +1,62 @@
+local _setup = {}
+
+local function normalize_path()
+	if not _setup.save_dir_path then
+		return
+	end
+
+	_setup.save_dir_path = vim.fn.fnamemodify(_setup.save_dir_path, ":p")
+end
+
+local function normalize_setup()
+	if not _setup.themes then
+		error("chameleon: 'themes' is a required field inside the config")
+	end
+
+	for index, value in ipairs(_setup.themes) do
+		if type(value) == "string" then
+			_setup.themes[index] = {
+				name = value,
+				colorscheme = value,
+			}
+		end
+		if value.name and not value.colorscheme then
+			local tmp = vim.tbl_deep_extend("force", _setup.themes[index], value)
+			tmp.colorscheme = tmp.name
+			_setup.themes[index] = tmp
+		end
+	end
+end
+
+local function setup(user_config)
+	_setup = vim.tbl_deep_extend("keep", user_config, {})
+
+	normalize_setup()
+	normalize_path()
+end
+
+local function get_config()
+	return _setup
+end
+
+local function save_dir_enabled()
+	return _setup.save_dir_path ~= nil
+end
+
+local function name_to_config(theme_name)
+	for _, value in ipairs(_setup.themes) do
+		if value.name == theme_name then
+			return value
+		end
+	end
+	return {}
+end
+
+return {
+	setup = setup,
+	normalize_path = normalize_path,
+	normalize_setup = normalize_setup,
+	save_dir_enabled = save_dir_enabled,
+	get_config = get_config,
+	name_to_config = name_to_config,
+}

lua/chameleon/init.lua

@@ -0,0 +1,41 @@
+local config = require("chameleon.config")
+local loader = require("chameleon.loader")
+
+local switch = function(opts)
+	local theme_config = config.name_to_config(opts)
+
+	if theme_config.before and type(theme_config.before) == "string" then
+		local ok, before = pcall(loadstring, theme_config.before)
+		if not ok then
+			error("chameleon: failed executing 'before' action.")
+		end
+		if before then
+			before()
+		end
+	end
+
+	local ok, _ = pcall(vim.cmd, string.format("colorscheme %s", theme_config.colorscheme))
+	if not ok then
+		error(string.format("chameleon: theme is not loaded %s", theme_config.colorscheme))
+	end
+
+	if theme_config.after and type(theme_config.after) == "string" then
+		local ok, after = pcall(loadstring, theme_config.after)
+		if not ok then
+			error("chameleon: failed executing 'after' action.")
+		end
+		if after then
+			after()
+		end
+	end
+
+	if config.save_dir_enabled() then
+		loader.save(opts)
+	end
+end
+
+return {
+	switch = switch,
+	setup = config.setup,
+	restore = loader.restore,
+}

lua/chameleon/loader.lua

@@ -0,0 +1,63 @@
+local config = require("chameleon.config")
+
+local function save(theme_name)
+	local theme_config = config.name_to_config(theme_name)
+	local save_path = config.get_config().save_dir_path
+
+	local file = io.open(save_path, "r")
+	if file == nil then
+		error(string.format("chameleon: Invalid file path '%s' for saving theme choice.", save_path))
+	end
+
+	local before_str = "nil"
+	local after_str = "nil"
+
+	if theme_config.before then
+		before_str = theme_config.before
+	end
+
+	if theme_config.after then
+		after_str = theme_config.after
+	end
+
+	local config_content = "-- chameleon.nvim\n"
+		.. "-- This file is used to reload your theme settings on restart\n"
+		.. string.format("local colorscheme = '%s'\n", theme_config.colorscheme)
+		.. string.format("local before = %s\n", before_str)
+		.. string.format("local after = %s\n", after_str)
+		.. "return { colorscheme = colorscheme, before = before, after = after }"
+
+	local outfile = io.open(save_path, "w")
+	if outfile == nil then
+		error(string.format("chameleon: Invalid file path '%s' for saving theme choice.", save_path))
+	end
+	outfile:write(config_content)
+	outfile:close()
+end
+
+local function restore()
+	local save_path = config.get_config().save_dir_path
+	local saved_config = dofile(save_path)
+
+	if not saved_config.colorscheme then
+		return
+	end
+
+	if saved_config.before and type(saved_config.before) == "function" then
+		saved_config.before()
+	end
+
+	local ok, _ = pcall(vim.cmd, string.format("colorscheme %s", saved_config.colorscheme))
+	if not ok then
+		error("chameleon: theme not loaded")
+	end
+
+	if saved_config.after and type(saved_config.after) == "function" then
+		saved_config.after()
+	end
+end
+
+return {
+	save = save,
+	restore = restore,
+}

lua/telescope/_extensions/chameleon.lua

@@ -0,0 +1,60 @@
+local has_telescope, telescope = pcall(require, "telescope")
+
+if not has_telescope then
+	return
+end
+
+local finders = require("telescope.finders")
+local pickers = require("telescope.pickers")
+local telescope_config = require("telescope.config").values
+local actions = require("telescope.actions")
+local action_state = require("telescope.actions.state")
+local config = require("chameleon.config")
+local _chameleon = require("chameleon")
+
+local function create_finder()
+	local themes = config.get_config().themes
+
+	table.sort(themes, function(a, b)
+		return a.name:upper() < b.name:upper()
+	end)
+	return finders.new_table({
+		results = themes,
+		entry_maker = function(entry)
+			return {
+				value = entry,
+				display = entry.name,
+				ordinal = entry.name,
+			}
+		end,
+	})
+end
+
+local function chameleon(opts)
+	opts = opts or {}
+
+	pickers
+		.new(opts, {
+			prompt_title = "Chameleon: Themes",
+			finder = create_finder(),
+			previewer = false,
+			sorter = telescope_config.generic_sorter(opts),
+			attach_mappings = function(prompt_bufnr, _)
+				actions.select_default:replace(function()
+					actions.close(prompt_bufnr)
+					local selection = action_state.get_selected_entry()
+					local theme_config = selection.value
+					_chameleon.switch(theme_config.name)
+				end)
+				return true
+			end,
+		})
+		:find()
+end
+
+return telescope.register_extension({
+	setup = config.setup,
+	exports = {
+		chameleon = chameleon,
+	},
+})

plugin/chameleon.lua

@@ -0,0 +1,3 @@
+vim.api.nvim_create_user_command("Chameleon", function(opts)
+	require("chameleon").switch(opts.args)
+end, {})